1. Field of the Invention
The present invention relates to a method of fabricating a nanostructure array and a device including the nanostructure array and, more particularly, to a method of readily adjusting the size and shape of nanostructures and an interval between the nanostructures during a process of forming a nanostructure array and various devices having the nanostructure array.
2. Discussion of Related Art
With the development of application technology using nanoscale fine structures, much research is being carried out to effectively fabricate a nanoscale fine structure. However, it is still very difficult to precisely adjust the size and shape of a nanostructure, and many problems should be solved.
Nanosphere lithography technology involves depositing polystyrene nanospheres (a diameter of tens of nanometers to several micrometers) on a substrate to form a periodic particle array (PPA), depositing a metal film such as gold, silver or copper on the PPA, and removing the PPA in acetone with ultrasonic waves, thereby fabricating a metal nanoparticle array.
However, the method causes particles to be lumped together under a condition in which a particle interaction occurs due to dependency on the diameter of the nanospheres used as a mask, and has difficulty in finely adjusting the size of the particles and the interval between the particles. Particularly, in a nanostructure formed in the above method, the size and interval are correlated, and thus it is hard to independently control the size and interval.
To solve this problem, U.S. Laid-Open Patent Publication No. 2010/0080954 discloses photolithography technology that involves passing light through nanospheres two-dimensionally arranged on a photoresist (PR) layer to focus the light through the nanospheres, and thereby patterning an underlying PR area in a sub-wavelength scale.
Also, the publication discloses a method of controlling the pattern size by adjusting the amount of the light illuminated to the nanospheres. However, when a light dose illuminated to the nanosphere is low in an actual application of the technology, the size of a pore exposed and developed in the underlying PR is reduced, but an appropriate undercut structure for a subsequent lift-off process cannot be formed because of a shallow depth of exposure. On the other hand, when a light dose illuminated to the nanospheres is high, an appropriate undercut structure for a lift-off process is clearly formed, but a small nanostructure cannot be fabricated because the sensitized pore region becomes larger.